Fluid flux regulating units are used, when it comes to influencing the amount of fluid flow through a device and/or to influence the direction into which a fluid flow is directed. The influencing behaviour can be based on a variety of parameters, of course. For example, it is possible that a fluid flow is regulated in a way that the fluid pressure in a certain part of a machine is set to a certain pressure, in particular a constant pressure. In other cases, a simple opening and interruption of the fluid flow is intended. In yet other applications, an incoming fluid flow has to be selectively directed to a first fluid port, to a second fluid port or has to be split up into two parts, the respective part going to a first fluid port and to a second fluid port.
Fluid flux regulating units for performing these type of tasks are well known in the state of the art.
In U.S. Pat. No. 3,890,999 and in U.S. Pat. No. 2,777,458 fluid pressure regulators are described. These fluid pressure regulators have a fluid inlet port and a fluid outlet port. Fluid at a high pressure enters the pressure regulator through the fluid inlet port. Inside the fluid pressure regulator, the high fluid pressure is reduced to a lower set level. The fluid leaves the pressure regulator at reduced pressure through a fluid outlet port. For most applications, it is desired that the fluid outlet pressure is constant, independent on the fluid flux, passing through the fluid pressure regulator and in particular independent of the fluid pressure at the fluid inlet port.
Another problem is that fluid pressure regulators usually need a minimum outlet pressure to completely shut off. This is even true with a completely released pressure regulation spring device. Also, fluid pressure regulators according to the state of the art are usually ratio regulating devices, i.e. they are usually dependent on the inlet pressure, at least to a certain extent. Therefore, the diameter of the inlet orifice usually corresponds to the diameter of the fluid outlet, which in turn means that the regulator's output pressure will generally be affected by variations in the inlet pressure.
In EP 0 566 543 A1, DE 102 47 098 A1, U.S. Pat. No. 6,955,331 B2, U.S. Pat. No. 2,799,466, GB 846 106 and EP 1803 980 A1 actuated valves are described, where the fluid flow through the valve can be influenced by an external signal. The external signal can be applied as an external mechanical force (GB 846 106), as an electric signal (DE 102 47 098 A1, U.S. Pat. No. 2,799,466) or as a pilot pressure, applied to the valve (EP 0 566 543 A1, U.S. Pat. No. 6,955,331 B2, EP 1 803 980 A1). Even here it is desired that the signal to be applied to the actuated valve is essentially independent of other parameters, in particular independent of the fluid pressure on the high pressure side and/or on the low pressure side.
Although presently known fluid regulators and valves work quite well in practical applications, there is still room for further improvements. In particular, improvements are desired, when it comes to the independency of the respective device on the fluid pressure at the fluid inlet port and, where necessary, at the fluid outlet port.